The present invention relates to quick disconnect couplings and, more particularly, to a female quick disconnect coupler for pressurized fluid lines.
Quick connect couplings are used, for example, to connect hoses in hydraulic fluid lines. A typical application is on agricultural tractors to connect the tractor hydraulic system with attachable implements. The tractor typically includes one or more female coupler sockets, while the implements include one or more male coupler nipples. Pneumatic and other applications for such couplings are also well known.
Over the years changes have occurred in these systems which have required changes and performance improvements in the couplings. It is desirable for these couplings to connect regardless of trapped pressures within either the male or female side. It is also desirable for these couplings to connect without excessive leakage of fluid during attachment.
One early coupling design is shown in U.S. Pat. No. 4,077,433 where the female coupler includes a valve body slidable within the housing and a poppet valve internal to the valve body. The poppet valve is axially movable to engage a check valve in a male coupler when the male coupler is inserted into the female coupler. When low pressure is present in the male coupler, the poppet valve moves the check valve off its valve seat to allow flow from the female coupler to pass to the male coupler. When higher pressures are present in the male coupler, an internal passage in the poppet valve provides incoming fluid pressure to the rear surface of the poppet valve. Due to the differences in effective surface areas, the fluid pressure assists in driving the poppet valve against the check valve to move the check valve into an open position.
Other prior art designs accommodate for high pressures within the female coupler that make connection with a nonpressurized, or low pressurized, male coupler difficult. An example of this type of design is shown in U.S. Pat. No. 6,095,190 to Wilcox et al. In this design the female coupler has a relief valve integrated within a main valve which reduces pressure behind the main valve so as to permit easy coupling under pressure. However, an obstacle with this, and similar designs, is in the activation of the relief valve. If the seals within the valve are not balanced, the pressure force acting on valve will be difficult to overcome with a low pressurized male coupler. The addition of a relief valve also adds to the cost, complexity and size of the coupler.
In order to attach a nonpressurized, or low pressurized, female coupling with a high pressurized male coupler, prior art designs have added a hydraulic piston to the female half. An example of this type of design is shown in U.S. Pat. No. 6,016,835 to Maldavs. This design details a quick disconnect coupling wherein the female coupler includes a housing adapted to receive the male coupler. The housing includes a valve body slidable within the housing, and a poppet valve internal to the valve body. The piston surrounds the poppet valve to assist in moving the poppet valve against the check valve in the male coupler. Without the piston, pressure will act on both sides of the male half valve. Therefore, in order to force the male valve open, the pressure in the female half must exceed the pressure in the male half. With the addition of the hydraulic piston, the amount of area that the female pressure will act upon can be doubled or tripled. Therefore, a much higher force pushes through the female half poppet and opens the male half valve using much lower pressures. The obstacle with this type of design is that the piston is independent of the internal balancing seals so that you may have an unbalanced force within the female coupler tending to uncouple the coupling.
The present invention provides improvements in female couplers which overcome one or more of the aforesaid problems encountered with prior art female couplers.
According to one feature of the present invention, a female coupler, used as a fluid connector, includes an exterior portion, an interior portion and a poppet valve. The exterior portion has an internal bore with an open forward end adapted to receive a male coupler, a flow port for supplying pressurized fluid to the internal bore, an internal surface with at least one groove section and at least one outlet passage through the exterior portion for fluid communication with the at least one groove section. The interior portion is disposed within the internal bore and is axially movable within the exterior portion from a first position, in which fluid is sealed within the female coupler, to a second position, in which fluid can exit the female coupler through the at least one groove section. The interior portion includes a main cavity opening towards the exterior portion forward end and a valve seat. The poppet valve is slidably received within the interior portion and is spring-biased forwardly against the valve seat to normally prevent fluid flow through the valve portion. The poppet valve includes a valve seal portion, a forward projection adapted to engage a check valve in the male coupler when the male coupler is received in the exterior portion.
Another feature of the noted female coupler has the interior portion including a body and a seal gland. The seal gland houses a peripheral seal that is axially spaced from the at least one groove section when the interior portion is in the first position and is axially aligned with the at least one groove section when the interior portion is in the second position. A further feature has the seal gland including a first balanced seal residing in a circumferential groove in its rear external surface and the peripheral seal being balanced and residing in a circumferential groove in its front external surface. The exterior portion includes a balanced seal residing in a circumferential groove in its interior surface.
Still another feature has the noted female coupler including a generally tubular sleeve with an internal bore with an open forward end, disposed within the interior portion and being axially movable, relative to the interior portion, from a locked position with the interior portion to an unlocked position. The poppet valve can further include a rearward tubular portion received within the sleeve and having an outside diameter slightly less than the inside diameter of the sleeve. Further, the sleeve can have an internal shoulder for limiting the axial movement of the poppet valve.
In a preferred embodiment, the poppet valve has a pressure relief valve fixedly positioned within with a pressure relief pin located at its front axial end. The relief pin is adapted to contact the male coupler check valve and relieve pressure within the female coupler when the interior portion is in the first position and prior to engagement of the forward projection with the male coupler. Still yet another feature has the relief valve including a valve body having an internal cavity that houses a spool with an external circumferential groove for receiving a balanced seal that prevents the escape of fluid from the female coupler prior to the pin contacting the male coupler check valve.
In another preferred embodiment, a generally annular piston is disposed and slidably received within the exterior portion. The piston includes a tubular main portion, a radially enlarged annular end portion and a central bore for fluid flow. The tubular main portion is disposed and slidably received within the interior portion and has an outer surface in sealing contact with the inner surface of the interior portion. The radially enlarged end portion engages the interior portion and assists in moving the poppet valve axially against excessive pressures in the male coupler.
Another feature of the female coupler includes a sleeve, having an internal bore with an open forward end, disposed within the interior portion and axially movable relative to the same from a locked position with the interior portion to an unlocked position. Further, the poppet valve has a rearward tubular portion nested within the sleeve and an outside diameter slightly less than the inside diameter of the sleeve. Further features and advantages of the present invention will become apparent to those skilled in the art upon review of the following specification in conjunction with the accompanying drawings.